Bimetallic catalyst, method of polymerization and bimodal polyolefins therefrom

ABSTRACT

Bimetallic catalysts, and methods of producing a bimetallic catalyst comprising a modified Ziegler-Natta catalyst and a metallocene are provided, in one embodiment the method including combining: (a) a Ziegler-Natta catalyst comprising a Group 4, 5 or 6 metal halide and/or oxide, optionally including a magnesium compound, with (b) a modifier compound (“modifier”), wherein the modifier compound is a Group 13 alkyl compound, to form a modified Ziegler-Natta catalyst. Also provided is a method of olefin polymerization using the bimetallic catalyst of the invention. The modified Ziegler-Natta catalyst is preferably non-activated, that is, it is unreactive towards olefin polymerization alone. In one embodiment, the molar ratio of the Group 13 metal (of the modifier) to the Group 4, 5 or 6 metal halide and/or oxide is less than 10:1 in one embodiment. The bimetallic catalysts of the present invention are useful in producing bimodal polymers, particularly bimodal polyethylene, having a Polydispersity (Mw/Mn) of from 12 to 50. These bimodal polyolefins are useful in such articles as pipes and films.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to provisional patentapplication U.S. Ser. No. 60/437,410 filed on Dec. 31, 2002.

BACKGROUND

1. Field of Invention

The present invention relates to bimetallic catalysts, methods ofproducing these catalysts, and methods of polymerizing olefins usingthese bimetallic catalysts. More particularly, the present inventionrelates to a bimetallic catalyst including a modified Ziegler-Nattacatalyst, and methods of producing bimodal polyolefins therefrom.

2. Description of Related Art

The polymerization processes described herein can be a solution, gasphase, slurry phase or high-pressure process. As discussed in greaterdetail below, gas phase or slurry phase polymerization processes arepreferred, involving catalysts and olefin monomers, at least one ofwhich is ethylene or propylene. As reflected in the patent literature, agreat deal of effort has been expended towards discovering improvementsin such processes. Some of those patents are identified herein. Theimprovements offered by the inventions described herein are set forth ingreater detail below.

SUMMARY

One aspect of the present invention is directed to a method of producinga modified Ziegler-Natta catalyst, the method in one embodimentcomprising combining: (a) a Ziegler-Natta catalyst comprising a Group 4,5 or 6 metal halide and/or oxide, optionally including a magnesiumcompound, with (b) a modifier compound (“modifier”), wherein themodifier compound is a Group 13 alkyl compound or mixture of compounds,to form a modified Ziegler-Natta catalyst. The modified Ziegler-Nattacatalyst is preferably non-activated, that is, it is unreactive towardsolefin polymerization alone. In one embodiment, the modifier can bedescribed by the formula AlX_(n)R_(3-n), wherein Al is aluminum, X isindependently selected from the group consisting of halides, preferablyfluoride, chloride or bromide, C₁ to C₂₀ alkoxides, C₁ to C₂₀alkylamides, and combinations thereof; and R is independently selectedfrom the group consisting of C₁ to C₂₀ alkyls and C₆ to C₂₀ aryls; andwherein n is 0, 1, 2 or 3 in one embodiment, and in a particularembodiment, n is 1, 2 or 3; and further, wherein the modifier may be ablend of compounds described by the formula. In one embodiment, themolar ratio of the Group 13 metal (of the modifier) to the Group 4, 5 or6 metal halide and/or oxide of the Ziegler-Natta catalyst is less than10:1.

Another aspect of the present invention is a method of producing abimetallic catalyst, the method comprising combining the a Ziegler-Nattacatalyst and a second catalyst component, preferably a metallocenecatalyst, to form the bimetallic catalyst; wherein the Ziegler-Nattacatalyst may be modified before or after combining with the secondcatalyst component. The method of forming the bimetallic catalystresults in a bimetallic catalyst comprising a Ziegler-Natta catalystcomponent (“Ziegler-Natta catalyst”) and a metallocene catalystcomponent (“metallocene catalyst”) that can be supported on, forexample, an inorganic oxide support and activated by, for example, useof an alumoxane and/or other aluminum alkyls.

The bimetallic catalysts of the present invention are useful inproducing bimodal polyolefins, particularly bimodal polyethylene, havinga Polydispersity (Mw/Mn) of from 12 to 30 and a value of Mz of fromgreater than 1,000,000 in one embodiment. The bimodal polyethylene mayhave other characteristics such as a density in the range of from 0.94to 0.98 g/cc in a particular embodiment, and is preferably produced in asingle reactor in one step. These bimodal polyolefins are useful in sucharticles as pipes, films, and blow molding applications (e.g., bottles,pails and other containers).

DETAILED DESCRIPTION

Introduction

As used herein, in reference to Periodic Table “Groups” of Elements, the“new” numbering scheme for the Periodic Table Groups are used as in theCRC HANDBOOK OF CHEMISTRY AND PHYSICS (David R. Lide ed., CRC Press81^(st) ed. 2000).

As used herein, structural formulas are employed as is commonlyunderstood in the chemical arts; lines (“—”) used to representassociations between a metal atom (“M”, Group 3 to Group 12 atoms) and aligand, ligand atom or atom (e.g., cyclopentadienyl, nitrogen, oxygen,halogen ions, alkyl, etc.), as well as the phrases “associated with”,“bonded to” and “bonding”, are not limited to representing a certaintype of chemical bond, as these lines and phrases are meant to representa “chemical bond”; a “chemical bond” defined as an attractive forcebetween atoms that is strong enough to permit the combined aggregate tofunction as a unit, or “compound”.

An aspect of the present invention is directed to a modifiedZiegler-Natta catalyst, and a method of making the modifiedZiegler-Natta catalyst. Another aspect of the present invention includesa bimetallic catalyst that comprises the modified Ziegler-Nattacatalyst, and method of making the bimetallic catalyst. Polymerizationprocesses disclosed herein involve contacting olefinic monomers with thebimetallic catalyst of the invention. The olefins and bimetalliccatalyst may be contacted in one or more reactors, preferably in onereactor, to produce a polyolefin product as described herein. As usedherein, the term “bimetallic catalyst” means any composition, mixture orsystem that includes at least two different catalyst compounds, at leastone of which is a so called “modified Ziegler-Natta catalyst” asdescribed herein. Each different catalyst can reside on a single supportparticle, so that the bimetallic catalyst is a supported bimetalliccatalyst. However, as used herein, the term bimetallic catalyst alsoincludes a system or mixture in which one of the catalysts components(e.g., the first catalyst compound) resides on one collection of supportparticles, and another catalyst (e.g., the second catalyst compound)resides on another collection of support particles. Preferably, in thatlatter instance, the two supported catalysts are introduced to a singlereactor, either simultaneously or sequentially, and polymerization isconducted in the presence of the bimetallic catalyst, i.e., the twocollections of supported catalysts.

Although a bimetallic catalyst can include more than two differentcatalysts, for purposes of discussing the invention herein, only two ofthose catalyst compounds are described in detail, i.e., the “firstcatalyst component” and the “second catalyst component,” each discussedbelow. The first catalyst component is a modified Ziegler-Natta catalystand the second catalyst component is a single site catalyst compoundsuch as, for example, a metallocene catalyst compound. Other single sitecatalysts such as so called Group 15-containing catalyst compounds asdisclosed in, for example, WO 99/01460; EP A1 0 893 454; EP A1 0 894005; U.S. Pat. No. 5,318,935; U.S. Pat. No. 5,889,128 U.S. Pat. No.6,333,389 B2 and U.S. Pat. No. 6,271,325 B1 may also be useful as thesecond catalyst component.

Various methods can be used to affix or bond one or two differentcatalysts to a support to form a bimetallic catalyst. For example, oneprocedure for preparing a supported bimetallic catalyst can includeproviding a supported first catalyst component, contacting a slurryincluding the first catalyst component and a non-polar hydrocarbon witha mixture (solution or slurry) that includes the second catalystcomponent, which may also include an activator. The procedure mayfurther include drying the resulting product that includes the first andsecond catalyst components and recovering a bimetallic catalyst.

First Catalyst Component

The bimetallic catalysts described herein include a “first catalystcomponent,” which is a modified Ziegler-Natta catalyst. Ziegler-Nattacatalysts are well known in the art and described, for example, inZIEGLER CATALYSTS 363-386 (G. Fink, R. Mulhaupt and H. H. Brintzinger,eds., Springer-Verlag 1995). Examples of such catalysts include thosecomprising Group 4, 5 or 6 transition metal oxides, alkoxides andchlorides (or combinations thereof), optionally in combination with amagnesium compound, internal and/or external electron donors, andsupport materials such as, for example, Group 13 and 14 inorganicoxides, as is known in the art and described in, for example, inPOLYPROPYLENE HANDBOOK 12-44 (Edward P. Moore, Jr., ed., HanserPublishers 1996) and, for example, U.S. Pat. No. 5,258,345.

In the present invention, the non-activated Ziegler-Natta catalyst iscontacted with a “modifier” (described below) to form an non-activatedmodified Ziegler-Natta catalyst or “modified Ziegler-Natta catalyst”,which is then combined with the second catalyst component, preferably ametallocene, to provide a bimetallic catalyst. In one embodiment, theZiegler-Natta catalyst comprises a Group 4, 5 or 6 transition metal,preferably selected from Group 4 and 5, and more preferably titanium,even more preferably derived from a titanium chloride compound. Inanother embodiment, the Ziegler-Natta catalyst further comprises anorganomagnesium compound. In certain embodiments of the invention, themodified Ziegler-Natta catalyst remains non-activated, both before andafter making contact with the modifier, for example, until after themodified Ziegler-Natta catalyst is combined with the metallocenecompound, and before polymerization is initiated. Desirably, themodified Ziegler-Natta catalyst component of the bimetallic catalystremains non-activated until contacted with olefin monomers in apolymerization reactor.

The term “non-activated’ means “not activated,” “not active,” or“inactive,” preferably such that the catalyst is not (without furthertreatment or modification) capable of promoting polymerization whencombined with monomers under polymerization conditions in a reactor.Preferably, an “non-activated” catalyst is one having either noactivity; or an activity of less than 10 grams polymer per gram ofcatalyst. Alternatively, in at least certain embodiments, a“non-activated” catalyst is one having an activity of less than 100grams polymer per gram of catalyst; and in other embodiments, annon-activated catalyst is one having an activity of less than 500 gramspolymer per gram of catalyst. Those skilled in the art will recognizethat the catalyst must be “activated” in some way before it is usefulfor promoting polymerization. As discussed below, activation istypically done by combining the catalyst compound (e.g., a Ziegler-Nattacatalyst) with an “activator.” Although the methods described hereinalso include various activation steps, for example, combining a catalystwith an activator such as TMA and water, those activation steps are notto be confused with catalyst “modification” as described herein. Whereasthe former results in an activated catalyst, the latter does not resultin an activated catalyst, even though the modifiers described hereinhave been used as co-catalysts or activators in other compositions orprocesses.

In one embodiment, the “modifier” recited herein is any compound orblend of compounds that includes at least one Group 13 metal, preferablyaluminum or boron, and an alkyl group (or alkoxy or alkylamide group).In one embodiment, the modifier can be described by the formulaAlX_(n)R_(3-n), wherein Al is aluminum, X is independently selected fromthe group consisting of halides, preferably fluoride, chloride orbromide, C₁ to C₂₀ alkoxides, C₁ to C₂₀ alkylamides, and combinationsthereof; and R is independently selected from the group consisting of C₁to C₂₀ alkyls and C₆ to C₂₀ aryls; and wherein n is 0, 1, 2 or 3 in oneembodiment, and in a particular embodiment, n is 1, 2 or 3, and in yet amore particular embodiment, n is 1 or 2; and wherein the modifier can bea blend of two or more compounds described by the formula. For example,the modifier, as used herein, may comprise a blend ofdiethylaluminumchloride and ethylaluminumdichloride in any desirableratio. The description of the modifier compound is not limited to itsphysical form, as it may be a neat liquid, a solution comprising asuitable diluent, a slurry in a diluent, or dry solid. In a particularembodiment the modifier includes at least one halide group. In anotherembodiment of the modifier, the modifier comprises aluminum compounds ofethyl or butyl, and at least one chloride. Non-limiting examples ofsuitable modifiers include diethyl aluminum chloride (DEAC),ethylaluminum sesquichloride (EASC), diethylaluminum ethoxide (DEAL-E),and mixtures thereof.

Other non-limiting examples of modifiers include: methylaluminumdichloride, ethylaluminum dichloride, isobutylaluminum dichloride,n-octylaluminum dichloride, methylaluminum sesquichloride, ethylaluminumsesquichloride, ethylaluminum sesquibromide, isobutylaluminumsesquichloride, dimethylaluminum chloride, diethylaluminum chloride,diethylaluminum bromide, diethylaluminum iodide, di-n-propylaluminumchloride, di-n-butylaluminum chloride, diisobutylaluminum chloride,di-n-octylaluminum chloride, diethylaluminum ethoxide,diisobutylaluminum ethoxide, bis(diisobutylaluminum) oxide, diethylboronmethoxide, dimethylboron chloride, diethylboron chloride,di-n-butylboron chloride, di-iso-butylboron chloride, and mixturesthereof.

Preferably, the molar ratio of the Group 13 metal to the transitionmetal (in the Ziegler-Natta catalyst) is less than 10:1. It iscontemplated that amounts of modifier represented by a molar ratio of10:1 or above may cause activation of the catalyst to occur, which isundesirable. A catalyst that becomes activated cannot be stored for anyappreciable period of time without suffering from degradation. Forexample, an activated catalyst may begin to degrade after only 1 week ofstorage. In certain embodiments of the method, the molar ratios of theGroup 13 metal in the modifier to the transition metal in theZiegler-Natta catalyst fall within certain ranges, for example, havingupper limits of 7:1; or 5:1; or 4:1; or 3:1; or even 2:1; and lowerlimits of 0.01:1, or 0.1:1 or 1:1, wherein the ranges can extend fromany combination of any of the foregoing lower limits to any of theforegoing upper limits. When the modifier includes chlorine, it ispreferable that the level of modifier have a molar ratio of 5:1 or lessbecause of the corrosivity of chlorine.

The order in which the modifier and/or activator contacts theZiegler-Natta catalyst is selected so that the highest catalyst activity(or productivity) is achieved. In one embodiment, the modifier is firstcontacted with a non-activated Ziegler-Natta catalyst, followed by (withor without isolation of the product) contacting the modifiednon-activated Ziegler-Natta catalyst with an activator. In anotherembodiment, the Ziegler-Natta catalyst is contacted simultaneously withthe modifier and activator. In a particular aspect of this latterembodiment, the activator is trimethylaluminum (TMA), and in yet a moreparticular embodiment of the latter embodiment, the modifier excludesTMA. In any of these embodiments, the Ziegler-Natta catalyst or modifiedZiegler Natta catalyst may be supported on a support material.

The phrase “isolation of the product” means, for example, removingdiluents used during preparation of the product (for example, theZiegler-Natta catalyst) that are not necessary for the final catalystcomposition.

In yet another more particular embodiment, the Ziegler-Natta catalyst isfirst supported, for example, affixed to a support such as an inorganicoxide, silica in one embodiment. This supported Ziegler-Natta catalystmay be combined with an organomagnesium compound in another embodiment,in any desirable order. The non-activated supported Ziegler-Nattacatalyst is then combined with a second catalyst compound, followed by(with or without isolating the product) contacting with the modifier. Inan alternate embodiment, the non-activated supported Ziegler-Nattacatalyst is first contacted with the modifier to form the modifiedZiegler-Natta catalyst (with or without isolation of the product)followed by contacting with the second catalyst component. The secondcatalyst component is preactivated in one embodiment, and in anotherembodiment, activated after combining with the supported Ziegler-Nattacatalyst. The resultant product is the bimetallic catalyst.

In one embodiment, the resultant bimetallic catalyst comprises a supportmaterial, a modified Ziegler-Natta catalyst, and an activator suitablefor the metallocene such as, for example, an alumoxane, tris-arylboraneor a ionic borate activator known in the art.

In an embodiment of the bimetallic catalyst, an activator suitable foractivating the metallocene, such as an alumoxane, is addedsimultaneously with the metallocene to the supported modifiedZiegler-Natta catalyst. The Ziegler-Natta catalyst or modifiedZiegler-Natta catalyst is then activated in one embodiment by contactingaluminum alkyl compound, for example trimethylaluminum (TMA), with thebimetallic catalyst either directly prior to entering the polymerizationreactor, or after entering the polymerization reactor. Preferably, anamount of water is also added to the polymerization reactor as well, inany suitable manner, to effectuate the activation of the modifiedZiegler-Natta component. In yet another embodiment, the modifier andactivator, preferably TMA, are added simultaneously to thenon-activated, preferably supported, Ziegler-Natta catalyst. In a moreparticular embodiment, a supported bimetallic catalyst comprising thenon-activated Ziegler-Natta catalyst is combined either prior toentering the polymerization reactor or in the polymerization reactorwith an amount of TMA sufficient to activate the Ziegler-Natta catalystsimultaneous with the addition of a modifier compound excluding TMA, themodifier added in an amount of less than a molar ratio of 10:1 aluminumof modifier-to-transition metal of Ziegler-Natta catalyst.

As described above, the Ziegler-Natta catalyst may be supported. Aspecific embodiment of forming the Ziegler-Natta catalyst includescontacting a support material, for example an inorganic oxide such asalumina or silica, with an organomagnesium compound that includes atleast one alkyl group to form a supported organomagnesium compound; thencontacting the supported organomagnesium compound with a Group 4, 5 or 6transition metal halide, alkoxide or oxide to form an non-activatedZiegler-Natta catalyst; then contacting the non-activated Ziegler-Nattacatalyst thus formed with an effective amount of a modifier as describedabove, in one embodiment modifiers such as diethylaluminum chloride(DEAC) or ethylaluminum sesquichloride (EASC) or diethylaluminumethoxide (DEAL-E), or blends thereof, to form a modified Ziegler-Nattacatalyst.

The organomagnesium compound that is optionally present in theZiegler-Natta catalyst and/or the modified Ziegler-Natta catalyst can berepresented by the formula RMgR′, where R′ and R are the same ordifferent C₂-C₁₂ alkyl groups, or C₄-C₁₀ alkyl groups, or C₄-C₈ alkylgroups. In another embodiment, Ziegler-Natta catalyst is formed bycontacting an organomagnesium compound with a Group 4 or 5 oxide,alkoxide or halide compound, preferably a titanium chloride compound,wherein the organomagnesium compound has the formula Mg(OR)₂ or R¹_(m)MgR² _(n); where R, R¹, and R² are C₁ to C₈ alkyl groups, and m andn are 0, 1 or 2.

The Ziegler-Natta catalyst can be combined with, placed on or otherwiseaffixed to the support or carrier in a variety of ways, either prior toor after modification of the Ziegler-Natta catalyst. Preferably, thefirst catalyst component is affixed to the support prior to modificationof the first catalyst component. In one of those ways, the supportmaterial is mixed with a non-polar hydrocarbon solvent to form a supportslurry. The support slurry is contacted with an organomagnesium compoundin one embodiment, which preferably then dissolves in the non-polarhydrocarbon of the support slurry to form a solution from which theorganomagnesium compound is then deposited onto the carrier.

Preferably, the amount of organomagnesium compound included in thesupport slurry is only that which will be deposited, physically orchemically, onto the support, e.g., being affixed to the hydroxyl groupson the support, and no more than that amount, since any excessorganomagnesium compound may cause undesirable side reactions duringlater polymerizations. Routine experimentation can be used to determinethe optimum amount of organomagnesium compound in the support slurry.For example, the organomagnesium compound can be added to the slurrywhile stirring the slurry, until the organomagnesium compound isdetected in the support solvent. Alternatively, the organomagnesiumcompound can be added in excess of the amount that is deposited onto thesupport, in which case any undeposited excess amount can be removed byfiltration and washing. The amount of organomagnesium compound (inmoles) based on the amount of dehydrated silica (in grams) ranges from0.2 mmol/g to 2.0 mmol/g.

In one embodiment the support slurry, optionally including theorganomagnesium compound, is contacted with an electron donor, such astetraethylorthosilicate (TEOS) or an organic alcohol having the formulaR″OH, where R″ is a C₁-C₁₂ alkyl group, or a C₁ to C₈ alkyl group, or aC₂ to C₄ alkyl group, and/or an ether or cyclic ether such astetrahydrofuran. In a particular embodiment, R″OH is n-butanol. Theamount of organic alcohol is preferably used in an amount effective toprovide an R″OH:Mg mol/mol ratio of from 0.2 to 1.5, or from 0.4 to 1.2,or from 0.6 to 1.1, or from 0.9 to 1.0.

The support slurry including the organomagnesium compound and theorganic alcohol can then be contacted with transition metal compound toform the Ziegler-Natta catalyst. Suitable transition metal compounds arecompounds of Group 4, 5 or 6 metals that are soluble in the non-polarhydrocarbon used to form the support slurry. Non-limiting examples oftransition metal compounds include, for example, titanium and vanadiumhalides, oxyhalides or alkoxyhalides, such as titanium tetrachloride(TiCl₄), vanadium tetrachloride (VCl₄) and vanadium oxytrichloride(VOCl₃), and titanium and vanadium alkoxides, wherein the alkoxidemoiety has a branched or unbranched alkyl group of 1 to 20 carbon atoms,preferably 1 to 6 carbon atoms. Mixtures of such transition metalcompounds may also be used. The amount of non-metallocene transitionmetal compound used is sufficient to give a transition metal tomagnesium mol/mol ratio of from 0.3 to 1.5, or from 0.5 to 0.8.

In one embodiment of the invention, a Ziegler-Natta catalyst comprisinga Group 4, 5 or 6 metal in one embodiment is first prepared, followed bycontacting with the modifier without isolating the Ziegler-Nattacatalyst prior to contacting with the modifier. This is an in situprocess whereby, for example, a modifier such as described herein, in aparticular embodiment an aluminum alkyl, is combined with theZiegler-Natta catalyst while still as a slurry in the diluent used tomake the Ziegler-Natta catalyst.

Second Catalyst Component

A second catalyst component is combined with the Ziegler-Natta componentto form a bimetallic catalyst. The Ziegler-Natta catalyst, modified ornot, and the second catalyst component may be combined in any number ofways using techniques known to one skilled in the art. In particular,the Ziegler-Natta catalyst may first be combined with the secondcatalyst component followed by contacting with the modifier in oneembodiment; and alternately, the Ziegler-Natta catalyst may be firstcontacted with the modifier, followed by contacting with the secondcatalyst component; wherein any embodiment may or may not include asupport material. For example, the second catalyst component can beintroduced to the support slurry including the modified Ziegler-Nattacatalyst. The solvent in the support slurry can then be removed in aconventional manner, such as by evaporation or filtering, to obtain thedry, supported bimetallic catalyst component.

In a preferred embodiment, the “second catalyst component” is ametallocene catalyst compound as described herein. Metallocene catalystcompounds are generally described throughout in, for example, 1 & 2METALLOCENE-BASED POLYOLEFINS (John Scheirs & W. Kaminsky eds., JohnWiley & Sons, Ltd. 2000); G. G. Hlatky in 181 COORDINATION CHEM. REV.243-296 (1999) and in particular, for use in the synthesis ofpolyethylene in 1 METALLOCENE-BASED POLYOLEFINS 261-377 (2000). Themetallocene catalyst compounds as described herein include “halfsandwich” and “full sandwich” compounds having one or more Cp ligands(cyclopentadienyl and ligands isolobal to cyclopentadienyl) bound to atleast one Group 3 to Group 12 metal atom, and one or more leavinggroup(s) bound to the at least one metal atom. Hereinafter, thesecompounds will be referred to as “metallocenes” or “metallocene catalystcompounds”. The metallocene catalyst compound is supported on a supportmaterial in a particular embodiment as described further below, and issupported with the modified Ziegler-Natta catalyst in a desirableembodiment, and even more preferably, the metallocene is co-immobilizedwith the modified Ziegler-Natta catalyst and an activator compoundcapable of activating the metallocene.

The Cp ligands are one or more rings or ring system(s), at least aportion of which includes π-bonded systems, such as cycloalkadienylligands and heterocyclic analogues. The ring(s) or ring system(s)typically comprise atoms selected from the group consisting of Groups 13to 16 atoms, and more particularly, the atoms that make up the Cpligands are selected from the group consisting of carbon, nitrogen,oxygen, silicon, sulfur, phosphorous, germanium, boron and aluminum andcombinations thereof, wherein carbon makes up at least 50% of the ringmembers. Even more particularly, the Cp ligand(s) are selected from thegroup consisting of substituted and unsubstituted cyclopentadienylligands and ligands isolobal to cyclopentadienyl, non-limiting examplesof which include cyclopentadienyl, indenyl, fluorenyl and otherstructures. Further non-limiting examples of such ligands includecyclopentadienyl, cyclopentaphenanthreneyl, indenyl, benzindenyl,fluorenyl, octahydrofluorenyl, cyclooctatetraenyl,cyclopentacyclododecene, phenanthrindenyl, 3,4-benzofluorenyl,9-phenylfluorenyl, 8-H-cyclopent[a]acenaphthylenyl, 7H-dibenzofluorenyl,indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl,hydrogenated versions thereof (e.g., 4,5,6,7-tetrahydroindenyl, or“H₄Ind”), substituted versions thereof (as described in more detailbelow), and heterocyclic versions thereof.

The metal atom “M” of the metallocene catalyst compound, as describedthroughout the specification and claims, may be selected from the groupconsisting of Groups 3 through 12 atoms and lanthanide Group atoms inone embodiment; and selected from the group consisting of Groups 3through 10 atoms in a more particular embodiment, and selected from thegroup consisting of Sc, Ti, Zr, Hf, V, Nb, Ta, Mn, Re, Fe, Ru, Os, Co,Rh, Ir, and Ni in yet a more particular embodiment; and selected fromthe group consisting of Groups 4, 5 and 6 atoms in yet a more particularembodiment, and a Ti, Zr, Hf atoms in yet a more particular embodiment,and Zr in yet a more particular embodiment. The oxidation state of themetal atom “M” may range from 0 to +7 in one embodiment; and in a moreparticular embodiment, is +1, +2, +3, +4 or +5; and in yet a moreparticular embodiment is +2, +3 or +4. The groups bound the metal atom“M” are such that the compounds described below in the formulas andstructures are electrically neutral, unless otherwise indicated. The Cpligand(s) form at least one chemical bond with the metal atom M to formthe “metallocene catalyst compound”. The Cp ligands are distinct fromthe leaving groups bound to the catalyst compound in that they are nothighly susceptible to substitution/abstraction reactions.

In one aspect of the invention, the one or more metallocene catalystcomponents of the invention are represented by the formula (I):Cp^(A)Cp^(B)MX_(n)  (I)wherein M is as described above; each X is chemically bonded to M; eachCp group is chemically bonded to M; and n is 0 or an integer from 1 to4, and either 1 or 2 in a particular embodiment.

The ligands represented by Cp^(A) and Cp^(B) in formula (I) may be thesame or different cyclopentadienyl ligands or ligands isolobal tocyclopentadienyl, either or both of which may contain heteroatoms andeither or both of which may be substituted by a group R. In oneembodiment, Cp^(A) and Cp^(B) are independently selected from the groupconsisting of cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl,and substituted derivatives of each.

Independently, each Cp^(A) and Cp^(B) of formula (I) may beunsubstituted or substituted with any one or combination of substituentgroups R. Non-limiting examples of substituent groups R as used instructure (I) as well as ring substituents in structures (Va-d) includegroups selected from the group consisting of hydrogen radicals, alkyls,alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys,aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls,aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys,acylaminos, aroylaminos, and combinations thereof.

More particular non-limiting examples of alkyl substituents R associatedwith formula (I) through (V) include methyl, ethyl, propyl, butyl,pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl, phenyl, methylphenyl,and tert-butylphenyl groups and the like, including all their isomers,for example tertiary-butyl, isopropyl, and the like. Other possibleradicals include substituted alkyls and aryls such as, for example,fluoromethyl, fluroethyl, difluroethyl, iodopropyl, bromohexyl,chlorobenzyl and hydrocarbyl substituted organometalloid radicalsincluding trimethylsilyl, trimethylgermyl, methyldiethylsilyl and thelike; and halocarbyl-substituted organometalloid radicals includingtris(trifluoromethyl)silyl, methylbis(difluoromethyl)silyl,bromomethyldimethylgermyl and the like; and disubstituted boron radicalsincluding dimethylboron for example; and disubstituted Group 15 radicalsincluding dimethylamine, dimethylphosphine, diphenylamine,methylphenylphosphine, Group 16 radicals including methoxy, ethoxy,propoxy, phenoxy, methylsulfide and ethylsulfide. Other substituents Rinclude olefins such as but not limited to olefinically unsaturatedsubstituents including vinyl-terminated ligands, for example 3-butenyl,2-propenyl, 5-hexenyl and the like. In one embodiment, at least two Rgroups, two adjacent R groups in one embodiment, are joined to form aring structure having from 3 to 30 atoms selected from the groupconsisting of carbon, nitrogen, oxygen, phosphorous, silicon, germanium,aluminum, boron and combinations thereof. Also, a substituent group Rgroup such as 1-butanyl may form a bonding association to the element M.

Each X in the formula (I) above and for the formulas/structures (II)through (V) below is independently selected from the group consistingof: any leaving group in one embodiment; halogen ions, hydrides, C₁ toC₁₂ alkyls, C₂ to C₁₂ alkenyls, C₆ to C₁₂ aryls, C₇ to C₂₀ alkylaryls,C₁ to C₁₂ alkoxys, C₆ to C₁₆ aryloxys, C₇ to C₁₈ alkylaryloxys, C₁ toC₁₂ fluoroalkyls, C₆ to C₁₂ fluoroaryls, and C₁ to C₁₂heteroatom-containing hydrocarbons and substituted derivatives thereofin a more particular embodiment; hydride, halogen ions, C₁ to C₆ alkyls,C₂ to C₆ alkenyls, C₇ to C₁₈ alkylaryls, C₁ to C₆ alkoxys, C₆ to C₁₄aryloxys, C₇ to C₁₆ alkylaryloxys, C₁ to C₆ alkylcarboxylates, C₁ to C₆fluorinated alkylcarboxylates, C₆ to C₁₂ arylcarboxylates, C₇ to C₁₈alkylarylcarboxylates, C₁ to C₆ fluoroalkyls, C₂ to C₆ fluoroalkenyls,and C₇ to C₁₈ fluoroalkylaryls in yet a more particular embodiment;hydride, chloride, fluoride, methyl, phenyl, phenoxy, benzoxy, tosyl,fluoromethyls and fluorophenyls in yet a more particular embodiment; C₁to C₁₂ alkyls, C₂ to C₁₂ alkenyls, C₆ to C₁₂ aryls, C₇ to C₂₀alkylaryls, substituted C₁ to C₁₂ alkyls, substituted C₆ to C₁₂ aryls,substituted C₇ to C₂₀ alkylaryls and C₁ to C₁₂ heteroatom-containingalkyls, C₁ to C₁₂ heteroatom-containing aryls and C₁ to C₁₂heteroatom-containing alkylaryls in yet a more particular embodiment;chloride, fluoride, C₁ to C₆ alkyls, C₂ to C₆ alkenyls, C₇ to C₁₈alkylaryls, halogenated C₁ to C₆ alkyls, halogenated C₂ to C₆ alkenyls,and halogenated C₇ to C₁₈ alkylaryls in yet a more particularembodiment; fluoride, methyl, ethyl, propyl, phenyl, methylphenyl,dimethylphenyl, trimethylphenyl, fluoromethyls (mono-, di- andtrifluoromethyls) and fluorophenyls (mono-, di-, tri-, tetra- andpentafluorophenyls) in yet a more particular embodiment; and fluoride inyet a more particular embodiment.

Other non-limiting examples of X groups in formula (I) include amines,amido compounds, phosphines, ethers, carboxylates, dienes, hydrocarbonradicals having from 1 to 20 carbon atoms, fluorinated hydrocarbonradicals (e.g., —C₆F₅ (pentafluorophenyl)), fluorinatedalkylcarboxylates (e.g., CF₃C(O)O⁻), hydrides and halogen ions andcombinations thereof. Other examples of X ligands include alkyl groupssuch as cyclobutyl, cyclohexyl, methyl, heptyl, tolyl, trifluoromethyl,tetramethylene, pentamethylene, methylidene, methyoxy, ethyoxy, propoxy,phenoxy, bis(N-methylanilide), dimethylamide, dimethylphosphide radicalsand the like. In one embodiment, two or more X's form a part of a fusedring or ring system.

In another aspect of the invention, the metallocene catalyst componentincludes those of formula (I) where Cp^(A) and Cp^(B) are bridged toeach other by at least one bridging group, (A), such that the structureis represented by formula (II):Cp^(A)(A)Cp^(B)MX_(n)  (II)

These bridged compounds represented by formula (II) are known as“bridged metallocenes”. Cp^(A), Cp^(B), M, X and n in structure (II) areas defined above for formula (I); and wherein each Cp ligand ischemically bonded to M, and (A) is chemically bonded to each Cp.Non-limiting examples of bridging group (A) include divalent hydrocarbongroups containing at least one Group 13 to 16 atom, such as but notlimited to at least one of a carbon, oxygen, nitrogen, silicon,aluminum, boron, germanium and tin atom and combinations thereof;wherein the heteroatom may also be C₁ to C₁₂ alkyl or aryl substitutedto satisfy neutral valency. The bridging group (A) may also containsubstituent groups R as defined above (for formula (I)) includinghalogen radicals and iron. More particular non-limiting examples ofbridging group (A) are represented by C₁ to C₆ alkylenes, substituted C₁to C₆ alkylenes, oxygen, sulfur, R′₂C═, R′₂Si═, —Si(R′)₂Si(R′₂)—,R′₂Ge═, R′P═ (wherein “═” represents two chemical bonds), where R′ isindependently selected from the group consisting of hydride,hydrocarbyl, substituted hydrocarbyl, halocarbyl, substitutedhalocarbyl, hydrocarbyl-substituted organometalloid,halocarbyl-substituted organometalloid, disubstituted boron,disubstituted Group 15 atoms, substituted Group 16 atoms, and halogenradical; and wherein two or more R′ may be joined to form a ring or ringsystem. In one embodiment, the bridged metallocene catalyst component offormula (II) has two or more bridging groups (A).

Other non-limiting examples of bridging group (A) include methylene,ethylene, ethylidene, propylidene, isopropylidene, diphenylmethylene,1,2-dimethylethylene, 1,2-diphenylethylene, 1,1,2,2-tetramethylethylene,dimethylsilyl, diethylsilyl, methyl-ethylsilyl,trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di(n-butyl)silyl,di(n-propyl)silyl, di(i-propyl)silyl, di(n-hexyl)silyl,dicyclohexylsilyl, diphenylsilyl, cyclohexylphenylsilyl,t-butylcyclohexylsilyl, di(t-butylphenyl)silyl, di(p-tolyl)silyl and thecorresponding moieties wherein the Si atom is replaced by a Ge or a Catom; dimethylsilyl, diethylsilyl, dimethylgermyl and diethylgermyl.

The position the bridging group is bound to each Cp is not limited, andin the case of indenyl or tetrahydroindenyl Cp ligands, the bridginggroup may be bound to either the so called “1” or “2” position alongeach ring, desirably the “1” position. While the structures in (Vc-f)show a particular position being bound to the bridging groups, this isonly one embodiment and not meant to be limiting.

In another embodiment, bridging group (A) may also be cyclic,comprising, for example 4 to 10, 5 to 7 ring members in a moreparticular embodiment. The ring members may be selected from theelements mentioned above, from one or more of B, C, Si, Ge, N and O in aparticular embodiment. Non-limiting examples of ring structures whichmay be present as or part of the bridging moiety are cyclobutylidene,cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene andthe corresponding rings where one or two carbon atoms are replaced by atleast one of Si, Ge, N and O, in particular, Si and Ge. The bondingarrangement between the ring and the Cp groups may be either cis-,trans-, or a combination.

The cyclic bridging groups (A) may be saturated or unsaturated and/orcarry one or more substituents and/or be fused to one or more other ringstructures. If present, the one or more substituents are selected fromthe group consisting of hydrocarbyl (e.g., alkyl such as methyl) andhalogen (e.g., F, Cl) in one embodiment. The one or more Cp groups whichthe above cyclic bridging moieties may optionally be fused to may besaturated or unsaturated and are selected from the group consisting ofthose having 4 to 10, more particularly 5, 6 or 7 ring members (selectedfrom the group consisting of C, N, O and S in a particular embodiment)such as, for example, cyclopentyl, cyclohexyl and phenyl. Moreover,these ring structures may themselves be fused such as, for example, inthe case of a naphthyl group. Moreover, these (optionally fused) ringstructures may carry one or more substituents. Illustrative,non-limiting examples of these substituents are hydrocarbyl(particularly alkyl) groups and halogen atoms.

The ligands Cp^(A) and Cp^(B) of formulae (I) and (II) are differentfrom each other in one embodiment, and the same in another embodiment.

In yet another aspect of the invention, the metallocene catalystcomponents include bridged mono-ligand metallocene compounds (e.g., monocyclopentadienyl catalyst components). In this embodiment, the at leastone metallocene catalyst component is a bridged “half-sandwich”metallocene as in, for example, U.S. Pat. No. 5,055,438, represented bythe formula (III):Cp^(A)(A)QMX_(n)  (III)wherein Cp^(A) is defined above and is bound to M; (A) is a bridginggroup bonded to Q and Cp^(A); and wherein an atom from the Q group isbonded to M; and n is 0 or an integer from 1 to 3; 1 or 2 in aparticular embodiment. In formula (III) above, Cp^(A), (A) and Q mayform a fused ring system. The X groups and n of formula (III) are asdefined above in formula (I) and (II). In one embodiment, Cp^(A) isselected from the group consisting of cyclopentadienyl, indenyl,tetrahydroindenyl, fluorenyl, substituted versions thereof, andcombinations thereof.

In formula (III), Q is a heteroatom-containing ligand in which thebonding atom (the atom that is bonded with the metal M) is selected fromthe group consisting of Group 15 atoms and Group 16 atoms in oneembodiment, and selected from the group consisting of nitrogen,phosphorus, oxygen or sulfur atom in a more particular embodiment, andnitrogen and oxygen in yet a more particular embodiment. Non-limitingexamples of Q groups include alkylamines, arylamines, mercaptocompounds, ethoxy compounds, carboxylates (e.g., pivalate), carbamates,azenyl, azulene, pentalene, phosphoyl, phosphinimine, pyrrolyl,pyrozolyl, carbazolyl, borabenzene other compounds comprising Group 15and Group 16 atoms capable of bonding with M.

In yet another aspect of the invention, the at least one metallocenecatalyst component is an unbridged “half sandwich” metallocenerepresented by the formula (IVa):Cp^(A)MQ_(q)X_(n)  (IVa)wherein Cp^(A) is defined as for the Cp groups in (I) and is a ligandthat is bonded to M; each Q is independently bonded to M; Q is alsobound to Cp^(A) in one embodiment; X is a leaving group as describedabove in (I); n ranges from 0 to 3, and is 1 or 2 in one embodiment; qranges from 0 to 3, and is 1 or 2 in one embodiment. In one embodiment,Cp^(A) is selected from the group consisting of cyclopentadienyl,indenyl, tetrahydroindenyl, fluorenyl, substituted version thereof, andcombinations thereof.

In formula (IVa), Q is selected from the group consisting of ROO⁻, RO—,R(O)—, —NR—, —CR₂—, —S—, —NR₂, —CR₃, —SR, —SiR₃, —PR₂, —H, andsubstituted and unsubstituted aryl groups, wherein R is selected fromthe group consisting of C₁ to C₆ alkyls, C₆ to C₁₂ aryls, C₁ to C₆alkylamines, C₆ to C₁₂ alkylarylamines, C₁ to C₆ alkoxys, C₆ to C₁₂aryloxys, and the like. Non-limiting examples of Q include C₁ to C₁₂carbamates, C₁ to C₁₂ carboxylates (e.g., pivalate), C₂ to C₂₀ allyls,and C₂ to C₂₀ heteroallyl moieties.

Described another way, the “half sandwich” metallocenes above can bedescribed as in formula (IVb), such as described in, for example, U.S.Pat. No. 6,069,213:Cp^(A)M(Q₂GZ)X_(n) orT(Cp^(A)M(Q₂GZ)X_(n))_(m)  (IVb)

-   wherein M, Cp^(A), X and n are as defined above;-   Q₂GZ forms a polydentate ligand unit (e.g., pivalate), wherein at    least one of the Q groups form a bond with M, and is defined such    that each Q is independently selected from the group consisting of    —O—, —NR—, —CR₂— and —S—; G is either carbon or silicon; and Z is    selected from the group consisting of R, —OR, —NR₂, —CR₃, —SR,    —SiR₃, —PR₂, and hydride, providing that when Q is —NR—, then Z is    selected from the group consisting of —OR, —NR₂, —SR, —SiR₃, —PR₂;    and provided that neutral valency for Q is satisfied by Z; and    wherein each R is independently selected from the group consisting    of C₁ to C₁₀ heteroatom containing groups, C₁ to C₁₀ alkyls, C₆ to    C₁₂ aryls, C₆ to C₁₂ alkylaryls, C₁ to C₁₀ alkoxys, and C₆ to C₁₂    aryloxys;-   n is 1 or 2 in a particular embodiment; and-   T is a bridging group selected from the group consisting of C₁ to    C₁₀ alkylenes, C₆ to C₁₂ arylenes and C₁ to C₁₀ heteroatom    containing groups, and C₆ to C₁₂ heterocyclic groups; wherein each T    group bridges adjacent “Cp^(A)M(Q₂GZ)X_(n)” groups, and is    chemically bonded to the Cp^(A) groups.-   m is an integer from 1 to 7; m is an integer from 2 to 6 in a more    particular embodiment.

In another aspect of the invention, the at least one metallocenecatalyst component can be described more particularly in structures(Va), (Vb), (Vc), (Vd) (Ve) and (Vf):

-   wherein in structures (Va) to (Vf) M is selected from the group    consisting of Group 3 to Group 12 atoms, and selected from the group    consisting of Group 3 to Group 10 atoms in a more particular    embodiment, and selected from the group consisting of Group 3 to    Group 6 atoms in yet a more particular embodiment, and selected from    the group consisting of Group 4 atoms in yet a more particular    embodiment, and selected from the group consisting of Zr and Hf in    yet a more particular embodiment; and is Zr in yet a more particular    embodiment;-   wherein Q in (Va-ii) is selected from the group consisting of    alkylenes, aryls, arylenes, alkoxys, aryloxys, amines, arylamines    (e.g., pyridyl) alkylamines, phosphines, alkylphosphines,    substituted alkyls, substituted aryls, substituted alkoxys,    substituted aryloxys, substituted amines, substituted alkylamines,    substituted phosphines, substituted alkylphosphines, carbamates,    heteroallyls, carboxylates (non-limiting examples of suitable    carbamates and carboxylates include trimethylacetate,    trimethylacetate, methylacetate, p-toluate, benzoate,    diethylcarbamate, and dimethylcarbamate), fluorinated alkyls,    fluorinated aryls, and fluorinated alkylcarboxylates; wherein the    saturated groups defining Q comprise from 1 to 20 carbon atoms in    one embodiment; and wherein the aromatic groups comprise from 5 to    20 carbon atoms in one embodiment;-   wherein each R* is independently: selected from the group consisting    of hydrocarbylenes and heteroatom-containing hydrocarbylenes in one    embodiment; and selected from the group consisting of alkylenes,    substituted alkylenes and heteroatom-containing hydrocarbylenes in    another embodiment; and selected from the group consisting of C₁ to    C₁₂ alkylenes, C₁ to C₁₂ substituted alkylenes, and C₁ to C₁₂    heteroatom-containing hydrocarbylenes in a more particular    embodiment; and selected from the group consisting of C₁ to C₄    alkylenes in yet a more particular embodiment; and wherein both R*    groups are identical in another embodiment in structures (Vb-f);-   A is as described above for (A) in structure (II), and more    particularly, selected from the group consisting of a chemical bond,    —O—, —S—, —SO₂—, —NR—, ═SiR₂, ═GeR₂, ═SnR₂, —R₂SiSiR₂—, RP═, C₁ to    C₁₂ alkylenes, substituted C₁ to C₁₂ alkylenes, divalent C₄ to C₁₂    cyclic hydrocarbons and substituted and unsubstituted aryl groups in    one embodiment; and selected from the group consisting of C₅ to C₈    cyclic hydrocarbons, —CH₂CH₂—, ═CR₂ and ═SiR₂ in a more particular    embodiment; wherein and R is selected from the group consisting of    alkyls, cycloalkyls, aryls, alkoxys, fluoroalkyls and    heteroatom-containing hydrocarbons in one embodiment; and R is    selected from the group consisting of C₁ to C₆ alkyls, substituted    phenyls, phenyl, and C₁ to C₆ alkoxys in a more particular    embodiment; and R is selected from the group consisting of methoxy,    methyl, phenoxy, and phenyl in yet a more particular embodiment;-   wherein A may be absent in yet another embodiment, in which case    each R* is defined as for R¹-R¹³;-   each X is as described above in (I);-   n is an integer from 0 to 4, and from 1 to 3 in another embodiment,    and 1 or 2 in yet another embodiment; and-   R¹ through R¹³ (and R^(4′) through R^(7′) and R^(10′) through    R^(13′)) are independently: selected from the group consisting of    hydrogen radical, halogen radicals, C₁ to C₁₂ alkyls, C₂ to C₁₂    alkenyls, C₆ to C₁₂ aryls, C₇ to C₂₀ alkylaryls, C₁ to C₁₂ alkoxys,    C₁ to C₁₂ fluoroalkyls, C₆ to C₁₂ fluoroaryls, and C₁ to C₁₂    heteroatom-containing hydrocarbons and substituted derivatives    thereof in one embodiment; selected from the group consisting of    hydrogen radical, fluorine radical, chlorine radical, bromine    radical, C₁ to C₆ alkyls, C₂ to C₆ alkenyls, C₇ to C₁₈ alkylaryls,    C₁ to C₆ fluoroalkyls, C₂ to C₆ fluoroalkenyls, C₇ to C₁₈    fluoroalkylaryls in a more particular embodiment; and hydrogen    radical, fluorine radical, chlorine radical, methyl, ethyl, propyl,    isopropyl, butyl, isobutyl, tertiary butyl, hexyl, phenyl,    2,6-di-methylphenyl, and 4-tertiarybutylphenyl groups in yet a more    particular embodiment; wherein adjacent R groups may form a ring,    either saturated, partially saturated, or completely saturated.

The structure of the metallocene catalyst component represented by (Va)may take on many forms such as disclosed in, for example, U.S. Pat. No.5,026,798, U.S. Pat. No. 5,703,187, and U.S. Pat. No. 5,747,406,including a dimer or oligomeric structure, such as disclosed in, forexample, U.S. Pat. No. 5,026,798 and U.S. Pat. No. 6,069,213.

In a particular embodiment of the metallocene represented in (Vd), R¹and R² form a conjugated 6-membered carbon ring system that may or maynot be substituted.

Non-limiting examples of metallocene catalyst components consistent withthe description herein include:

-   cyclopentadienylzirconium X_(n),-   indenylzirconium X_(n),-   (1-methylindenyl)zirconium X_(n),-   (2-methylindenyl)zirconium X_(n),-   (1-propylindenyl)zirconium X_(n),-   (2-propylindenyl)zirconium X_(n),-   (1-butylindenyl)zirconium X_(n),-   (2-butylindenyl)zirconium X_(n),-   (methylcyclopentadienyl)zirconium X_(n),-   tetrahydroindenylzirconium X_(n),-   (pentamethylcyclopentadienyl)zirconium X_(n),-   cyclopentadienylzirconium X_(n),-   pentamethylcyclopentadienyltitanium X_(n),-   tetramethylcyclopentyltitanium X_(n),-   1,2,4-trimethylcyclopentadienylzirconium X_(n),-   dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(cyclopentadienyl)zirconium    X_(n),-   dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2,3-trimethylcyclopentadienyl)zirconium    X_(n),-   dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2-dimethylcyclopentadienyl)zirconium    X_(n),-   dimethylsilyl(1,2,3,4-tetramethyl-cyclopentadienyl)(2-methylcyclopentadienyl)zirconium    X_(n),-   dimethylsilyl(cyclopentadienyl)(indenyl)zirconium X_(n),-   dimethylsilyl(2-methylindenyl)(fluorenyl)zirconium X_(n),-   diphenylsilyl(1,2,3,4-tetramethyl-cyclopentadienyl)(3-propylcyclopentadienyl)zirconium    X_(n),-   dimethylsilyl (1,2,3,4-tetramethylcyclopentadienyl)    (3-t-butylcyclopentadienyl)zirconium X_(n),-   dimethylgermyl(1,2-dimethylcyclopentadienyl)(3-isopropylcyclopentadienyl)zirconium    dimethylsilyl(1,2,3,4-tetramethyl-cyclopentadienyl)(3-methylcyclopentadienyl)zirconium    X_(n),-   diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium X_(n),-   diphenylmethylidene(cyclopentadienyl)(indenyl)zirconium X_(n),-   iso-propylidenebis(cyclopentadienyl)zirconium X_(n),-   iso-propylidene(cyclopentadienyl)(9-fluorenyl)zirconium X_(n),-   iso-propylidene(3-methylcyclopentadienyl)(9-fluorenyl)zirconium    X_(n),-   ethylenebis(9-fluorenyl)zirconium X_(n),-   meso-ethylenebis(1-indenyl)zirconium X_(n),-   ethylenebis(1-indenyl)zirconium X_(n),-   ethylenebis(2-methyl-1-indenyl)zirconium X_(n),-   ethylenebis(2-methyl-4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   ethylenebis(2-propyl-4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   ethylenebis(2-isopropyl-4,5,6,7-tetrahydro-1-indenyl)zirconium    X_(n),-   ethylenebis(2-butyl-4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   ethylenebis(2-isobutyl-4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   dimethylsilyl(4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   diphenyl(4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium X_(n),-   dimethylsilylbis(cyclopentadienyl)zirconium X_(n),-   dimethylsilylbis(9-fluorenyl)zirconium X_(n),-   dimethylsilylbis(1-indenyl)zirconium X_(n),-   dimethylsilylbis(2-methylindenyl)zirconium X_(n),-   dimethylsilylbis(2-propylindenyl)zirconium X_(n),-   dimethylsilylbis(2-butylindenyl)zirconium X_(n),-   diphenylsilylbis(2-methylindenyl)zirconium X_(n),-   diphenylsilylbis(2-propylindenyl)zirconium X_(n),-   diphenylsilylbis(2-butylindenyl)zirconium X_(n),-   dimethylgermylbis(2-methylindenyl)zirconium X_(n),-   dimethylsilylbis(tetrahydroindenyl)zirconium X_(n),-   dimethylsilylbis(tetramethylcyclopentadienyl)zirconium X_(n),-   dimethylsilyl(cyclopentadienyl)(9-fluorenyl)zirconium X_(n),-   diphenylsilyl(cyclopentadienyl)(9-fluorenyl)zirconium X_(n),-   diphenylsilylbis(indenyl)zirconium X_(n),-   cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(cyclopentadienyl)zirconium    X_(n),-   cyclotetramethylenesilyl(tetramethylcyclopentadienyl)(cyclopentadienyl)zirconium    X_(n),-   cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2-methylindenyl)zirconium    X_(n),-   cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(3-methylcyclopentadienyl)zirconium    X_(n),-   cyclotrimethylenesilylbis(2-methylindenyl)zirconium X_(n),-   cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2,3,5-trimethylcyclopentadienyl)zirconium    X_(n),-   cyclotrimethylenesilylbis(tetramethylcyclopentadienyl)zirconium    X_(n),-   dimethylsilyl(tetramethylcyclopentadieneyl)(N-tert-butylamido)titanium    X_(n),-   bis(cyclopentadienyl)chromium X_(n),-   bis(cyclopentadienyl)zirconium X_(n),-   bis(n-butylcyclopentadienyl)zirconium X_(n),-   bis(n-dodecyclcyclopentadienyl)zirconium X_(n),-   bis(ethylcyclopentadienyl)zirconium X_(n),-   bis(iso-butylcyclopentadienyl)zirconium X_(n),-   bis(iso-propylcyclopentadienyl)zirconium X_(n),-   bis(methylcyclopentadienyl)zirconium X_(n),-   bis(n-oxtylcyclopentadienyl)zirconium X_(n),-   bis(n-pentylcyclopentadienyl)zirconium X_(n),-   bis(n-propylcyclopentadienyl)zirconium X_(n),-   bis(trimethylsilylcyclopentadienyl)zirconium X_(n),-   bis(1,3-bis(trimethylsilyl)cyclopentadienyl)zirconium X_(n),-   bis(1-ethyl-2-methylcyclopentadienyl)zirconium X_(n),-   bis(1-ethyl-3-methylcyclopentadienyl)zirconium X_(n),-   bis(pentamethylcyclopentadienyl)zirconium X_(n),-   bis(pentamethylcyclopentadienyl)zirconium X_(n),-   bis(1-propyl-3-methylcyclopentadienyl)zirconium X_(n),-   bis(1-n-butyl-3-methylcyclopentadienyl)zirconium X_(n),-   bis(1-isobutyl-3-methylcyclopentadienyl)zirconium X_(n),-   bis(1-propyl-3-butylcyclopentadienyl)zirconium X_(n),-   bis(1,3-n-butylcyclopentadienyl)zirconium X_(n),-   bis(4,7-dimethylindenyl)zirconium X_(n),-   bis(indenyl)zirconium X_(n),-   bis(2-methylindenyl)zirconium X_(n),-   cyclopentadienylindenylzirconium X_(n),-   bis(n-propylcyclopentadienyl)hafnium X_(n),-   bis(n-butylcyclopentadienyl)hafnium X_(n),-   bis(n-pentylcyclopentadienyl)hafnium X_(n),-   (n-propyl cyclopentadienyl)(n-butyl cyclopentadienyl)hafnium X_(n),-   bis[(2-trimethylsilylethyl)cyclopentadienyl]hafnium X_(n),-   bis(trimethylsilyl cyclopentadienyl)hafnium X_(n),-   bis(2-n-propylindenyl)hafnium X_(n),-   bis(2-n-butylindenyl)hafnium X_(n),-   dimethylsilylbis(n-propylcyclopentadienyl)hafnium X_(n),-   dimethylsilylbis(n-butylcyclopentadienyl)hafnium X_(n),-   bis(9-n-propylfluorenyl)hafnium X_(n),-   bis(9-n-butylfluorenyl)hafnium X_(n),-   (9-n-propylfluorenyl)(2-n-propylindenyl)hafnium X_(n),-   bis(1-n-propyl-2-methylcyclopentadienyl)hafnium X_(n),-   (n-propylcyclopentadienyl)(1-n-propyl-3-n-butylcyclopentadienyl)hafnium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido)titanium    X_(n),-   dimethylsilyl(tetramethyleyclopentadienyl)(cyclobutylamido)titanium    X_(n),-   dimethylsilyl(tetramethyleyclopentadienyl)(cyclopentylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cycloundecylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(cyclododecylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titanium    X_(n),-   dimethylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclobutylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclopentylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium,    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cycloundecylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(cyclododecylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titanium    X_(n),-   methylphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclopropylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclobutylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclopentylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cycloheptylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclooctylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclononylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclodecylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cycloundecylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(cyclododecylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titanium    X_(n),-   diphenylsilyl(tetramethyleyclopentadienyl)(n-octylamido)titanium    X_(n),-   diphenylsilyl(tetramethyleyclopentadienyl)(n-decylamido)titanium    X_(n),-   diphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titanium    X_(n), and derivatives thereof.

By “derivatives thereof”, it is meant any substitution or ring formationas described above for structures (Va-f); and in particular, replacementof the metal “M” (Cr, Zr, Ti or Hf) with an atom selected from the groupconsisting of Cr, Zr, Hf and Ti, and selected from Zr and Hf in aparticular embodiment; and replacement of the “X” group with any of C₁to C₅ alkyls, C₆ aryls, C₆ to C₁₀ alkylaryls, fluorine or chlorine; n is1, 2 or 3.

It is contemplated that the metallocene catalysts components describedabove include their structural or optical or enantiomeric isomers(racemic mixture), and may be a pure enantiomer in one embodiment.

As used herein, a single, bridged, asymmetrically substitutedmetallocene catalyst component having a racemic and/or meso isomer doesnot, itself, constitute at least two different bridged, metallocenecatalyst components. In a preferred embodiment, the metallocenesdescribed herein are in their rac form.

The “metallocene catalyst component” useful in the present invention maycomprise any combination of any “embodiment” described herein.

Activators and Activation

In certain embodiments, the methods described herein further includecontacting either or both of the catalyst components with a catalystactivator, herein simply referred to as an “activator.” Preferably,depending on the type of catalyst, the catalyst activator is either a“first activator” or a “second activator”, corresponding to itsactivation of the first and second catalyst components, respectivelyAlternatively, when contacting bimetallic catalyst, e.g., theZiegler-Natta catalyst and the metallocene catalyst, the catalystactivator may be an activator composition that is a mixture of the“first activator” and the “second activator.” Preferably, activators(particularly the first activator) are present in the polymerizationreactor together with the bimetallic catalyst only when the monomers arealso present, and polymerization is to be initiated, often once theactivator and bimetallic catalyst are combined, the catalyst becomesactivated, and is accordingly subject to degradation. The activator,preferably a “first activator” is contacted or otherwise combined withthe first catalyst after the first catalyst is modified in oneembodiment, and the first activator is contacted simultaneously tocontacting the modifier with the Ziegler-Natta catalyst in anotherembodiment.

The first activator can be any one or a combination of materialscommonly employed to activate Ziegler-Natta catalysts, including metalalkyls, hydrides, alkylhydrides, alkylhalides (such as alkyllithiumcompounds), dialkylzinc compounds, trialkylboron compounds,trialkylaluminum compounds, alkylaluminum halides and hydrides, andtetraalkylgermanium compounds. Preferably, the first activator istrimethyl aluminum (TMA). The amount of the first activator ispreferably sufficient to give a molar ratio of activator metal atom(e.g., Al) to the transition metal in the Ziegler-Natta catalyst ofabout 10:1 to about 1000:1, preferably about 15:1 to about 300:1, andmost preferably about 20:1 to about 100:1. Preferably, the firstactivator is combined with water before or as it is injected into thereactor in order to contact the bimetallic catalyst; the molar ratio ofwater to first activator metal atom ranges from 0.01 to 5 in oneembodiment, and from 0.1 to 2 in another embodiment, and from 0.15 to 1in yet another embodiment.

The second activator suitable for activating the metal sites in thesecond catalyst component, for example, the metallocene catalyst, isdifferent from the first activator described above. Embodiments of suchactivators include Lewis acids such as cyclic or oligomericpoly(hydrocarbylaluminum oxides) and so called non-coordinatingactivators (“NCA”) (alternately, “ionizing activators” or“stoichiometric activators”), or any other compound that can convert aneutral metallocene catalyst component to a metallocene cation that isactive with respect to olefin polymerization. More particularly, it iswithin the scope of this invention to use Lewis acids such as alumoxane(e.g., “MAO”), modified alumoxane (e.g., “TIBAO”), and alkylaluminumcompounds as activators, and/or ionizing activators (neutral or ionic)such as tri(n-butyl)ammonium tetrakis(pentafluorophenyl)boron and/or atrisperfluorophenyl boron metalloid precursors to activate desirablemetallocenes described herein. MAO and other aluminum-based activatorsare well known in the art. Ionizing activators are well known in the artand are described by, for example, Eugene You-Xian Chen & Tobin J.Marks, Cocatalysts for Metal-Catalyzed Olefin Polymerization:Activators, Activation Processes, and Structure-Activity Relationships100(4) CHEMICAL REVIEWS 1391-1434 (2000). The activators may beassociated with or bound to a support, either in association with thecatalyst component (e.g., metallocene) or separate from the catalystcomponent, such as described by Gregory G. Hlatky, HeterogeneousSingle-Site Catalysts for Olefin Polymerization 100(4) CHEMICAL REVIEWS1347-1374 (2000).

The bimetallic catalyst, e.g., the enhanced support including theZiegler-Natta catalyst and the metallocene catalyst, may be contactedwith the catalyst activator in a number of ways. Preferably, thesupported bimetallic catalyst is contacted with a mixture including atleast the first and second activators.

Supports

In certain embodiments, an unsupported version of the bimetalliccatalyst described herein can be used in a polymerization process, i.e.,in which the monomers are contacted with a bimetallic catalyst that isnot supported. In other embodiments, a supported version of thebimetallic catalyst can be used. Preferably, the bimetallic catalyst issupported. Supports, methods of supporting, modifying, and activatingsupports for single-site catalyst such as metallocenes is discussed in,for example, 1 METALLOCENE-BASED POLYOLEFINS 173-218 (J. Scheirs & W.Kaminsky eds., John Wiley & Sons, Ltd. 2000). As used herein, the phrase“supported on a support material”, for example, means that the catalyst,activator, etc. is associated with, using any suitable means known inthe art, the “support material”. The terms “support” or “carrier”, asused herein, are used interchangeably and refer to any support material,a porous support material in one embodiment, including inorganic ororganic support materials. Non-limiting examples of support materialsinclude inorganic oxides and inorganic chlorides, and in particular suchmaterials as talc, clay, silica, alumina, magnesia, zirconia, ironoxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminumphosphate gel, and hydroxylated polymers such as polyvinylchloride andsubstituted polystyrene, functionalized or crosslinked organic supportssuch as polystyrene divinyl benzene polyolefins or polymeric compounds,and mixtures thereof, and graphite, in any of its various forms. In oneaspect of the invention, the support if present, is prepared by heatingsupport particles at a dehydration temperature of up to 600° C., or to800° C. In another aspect of the invention, the support, desirably aninorganic oxide, is pretreated such as by a fluoriding agent, silylatingagent, or by treating with a heterocyclic amine such as an indolecompound, either substituted or not.

In one or more specific embodiments, a support is first prepared,preferably in the manner described below; then that support is treated(e.g., combined with ingredients that form the first catalyst) toprovide a supported catalyst that includes the first catalyst component.In specific embodiments, that supported first catalyst is then treatedin the presence of the second catalyst component to provide a supportedbimetallic catalyst.

The support is preferably an inorganic material such as silicon oxide(silica) or aluminum oxide. Preferably, the support material is a drypowder, and in certain embodiments has an average particle size of from1 to 500 microns, and from 5 to 100 microns in another embodiment, andfrom 10 to 50 microns in yet another embodiment, and from 5 to 40microns in yet another embodiment. The surface area of the supportranges from 3 m²/g to 600 m²/g or more in one embodiment, and from 100to 500 m²/g in another embodiment, and from 200 to 400 m²/g in yetanother embodiment.

The dehydrated support can then be combined with a non-polar hydrocarbonto form a support slurry, which can be stirred and optionally heatedduring mixing.

A variety of non-polar hydrocarbons can be used to form the supportslurry, but any non-polar hydrocarbon selected should remain in liquidform at all relevant reaction temperatures, and the ingredients used toform the first catalyst component are preferably at least partiallysoluble in the non-polar hydrocarbon. Accordingly, the non-polarhydrocarbon is considered to be a “solvent” herein, even though incertain embodiments the ingredients are only partially soluble in thehydrocarbon. For example, the organomagnesium compound, alcohol andtransition metal compound of the first catalyst compound, described infurther detail below, are preferably at least partially soluble, andmore preferably completely soluble, in that hydrocarbon solvent at themixing temperatures described above.

Examples of suitable non-polar hydrocarbons include C₄-C₁₀ linear orbranched alkanes, cycloalkanes and aromatics, and oils such as mineraloil or silicon oil. More specifically, a non-polar alkane can beisopentane, hexane, isohexane, n-heptane, octane, nonane, or decane; anon-polar cycloalkane such as cyclohexane; or an aromatic such asbenzene, toluene, or ethylbenzene. Mixtures of different non-polarhydrocarbons can also be used.

The support slurry can be heated both during and after mixing of thesupport particles with the non-polar hydrocarbon solvent, but at thepoint when either or both of the catalysts are combined with the supportslurry, the temperature of the slurry is sufficiently low so thatneither of the catalysts are inadvertently activated. Thus, thetemperature of the support slurry (e.g., silica slurry) is preferablymaintained at a temperature below 90° C., e.g., from 25 to 70° C., oreven more narrowly from 40 to 60° C.

Polymerization Processes

As indicated elsewhere herein, the bimetallic catalysts described hereinare preferably used to make bimodal polyolefins, i.e., a polyolefinhaving a bimodal molecular weight distribution. Once the supportedbimetallic catalyst is prepared, as described above, a variety ofprocesses can be carried out using that catalyst. Among the varyingapproaches that can be used include procedures set forth in U.S. Pat.No. 5,525,678, in which those processes are modified to utilize thebimetallic catalysts described herein. The equipment, processconditions, reactants, additives and other materials will of course varyin a given process, depending on the desired composition and propertiesof the polyolefin being formed. In one embodiment, the polymerizationmay be carried out in a series of two or more steps and employ the sameor differing methods in each step of polymerization; and in a moreparticular embodiment, the bimodal catalyst is utilized in a singlereactor to produce the polymers, desirably bimodal polyethylenes,described herein.

The catalysts and catalyst systems described above, e.g., bimetalliccatalysts, can be used in a variety of polymerization processes, over awide range of temperatures and pressures. The temperatures may be in therange of from −60° C. to about 280° C., preferably from 50° C. to about200° C., and more preferably from 60° C. to 120° C.; and the pressuresemployed may be in the range from 1 atmosphere to about 500 atmospheresor higher.

The “polymerization reactor” referred to herein can be any suitablereactor useful for polymerizing olefins, and is not limited to thedescription herein. Embodiments of suitable polymerization processesinclude solution, gas phase, slurry phase and a high pressure process ora combination thereof. Particularly preferred is a gas phase or slurryphase polymerization of one or more olefins at least one of which isethylene or propylene.

In certain embodiments, the process of this invention is directed towarda solution, high pressure, slurry or gas phase polymerization process ofone or more olefin monomers having from 2 to 30 carbon atoms, preferably2 to 12 carbon atoms, and more preferably 2 to 8 carbon atoms; and evenmore preferably, the process of polymerization of the invention employscontacting the bimodal catalyst with ethylene and one or more olefinmonomers having from 3 to 10 carbon atoms. The invention is particularlywell suited to the polymerization of two or more olefin monomers ofethylene with one or more of propylene, 1-butene, 1-pentene,4-methyl-1-pentene, 1-hexane, 1-octane and 1-decene.

Other monomers useful in the process of the invention includeethylenically unsaturated monomers, diolefins having 4 to 18 carbonatoms, conjugated or nonconjugated dienes, polyenes, vinyl monomers andcyclic olefins. Non-limiting monomers useful in the invention mayinclude norbornene, norbornadiene, isobutylene, isoprene,vinylbenzocyclobutane, styrenes, alkyl substituted styrene, ethylidenenorbornene, dicyclopentadiene and cyclopentene.

In the most preferred embodiment of the process of the invention, acopolymer of ethylene is produced, where with ethylene, a comonomerhaving at least one α-olefin having from 4 to 15 carbon atoms,preferably from 4 to 12 carbon atoms, even more preferably from 3 to 10carbon atoms, and most preferably from 4 to 8 carbon atoms, ispolymerized in a gas phase or slurry process.

In another embodiment of the process of the invention, ethylene orpropylene is polymerized with at least two different comonomers,optionally one of which may be a diene, to form a terpolymer.

Typically in a gas phase polymerization process a continuous cycle isemployed where in one part of the cycle of a reactor system, the heat ofpolymerization heats a cycling gas stream, otherwise known as a recyclestream or fluidizing medium, in the reactor. This heat is removed fromthe recycle composition in another part of the cycle by a cooling systemexternal to the reactor. Generally, in a gas fluidized bed process forproducing polymers, a gaseous stream containing one or more monomers iscontinuously cycled through a fluidized bed in the presence of acatalyst under reactive conditions. The gaseous stream is withdrawn fromthe fluidized bed and recycled back into the reactor. Simultaneously,polymer product is withdrawn from the reactor and fresh monomer is addedto replace the polymerized monomer.

The reactor pressure in a gas phase process may vary from about 100 psig(690 kPa) to about 500 psig (3448 kPa), preferably in the range of fromabout 200 psig (1379 kPa) to about 400 psig (2759 kPa), more preferablyin the range of from about 250 psig (1724 kPa) to about 350 psig (2414kPa).

The reactor temperature in a gas phase process may vary from about 30°C. to about 120° C., preferably from about 60° C. to about 115° C., morepreferably in the range of from about 70° C. to 110° C., and mostpreferably in the range of from about 70° C. to about 95° C., wherein adesirable range includes any upper limit with any lower limit describedherein.

Other gas phase processes contemplated by the process of the inventioninclude those described in U.S. Pat. Nos. 5,627,242, 5,665,818 and5,677,375, and European publications EP-A-0 794 200, EP-A-0 802 202 andEP-B-634 421.

A slurry polymerization process generally uses pressures in the range offrom about 1 to about 50 atmospheres and even greater and temperaturesin the range of 0° C. to about 120° C. In a slurry polymerization, asuspension of solid, particulate polymer is formed in a liquidpolymerization diluent medium to which ethylene and comonomers and oftenhydrogen along with catalyst are added. The suspension including diluentis intermittently or continuously removed from the reactor where thevolatile components are separated from the polymer and recycled,optionally after a distillation, to the reactor. The liquid diluentemployed in the polymerization medium is typically an alkane having from3 to 7 carbon atoms, preferably a branched alkane. The medium employedare preferably liquid under the conditions of polymerization andrelatively inert. When a propane medium is used the process must beoperated above the reaction diluent critical temperature and pressure.Preferably, a hexane or an isobutane medium is employed.

A particle form polymerization, i.e., a type of slurry process, can beused wherein the temperature is kept below the temperature at which thepolymer goes into solution. Such technique is well known in the art, anddescribed in for instance U.S. Pat. No. 3,248,179. Other slurryprocesses include those employing a loop reactor and those utilizing aplurality of stirred reactors in series, parallel, or combinationsthereof. Non-limiting examples of slurry processes include continuousloop or stirred tank processes. Also, other examples of slurry processesare described in U.S. Pat. No. 4,613,484.

In an embodiment of the invention, a slurry or gas phase process is usedin the presence of bimetallic catalyst of the invention and in theabsence of or essentially free of any scavengers, such astriethylaluminum, trimethylaluminum, tri-isobutylaluminum andtri-n-hexylaluminum and diethyl aluminum chloride, dibutyl zinc and thelike. Such a process is described in PCT publication WO 96/08520 andU.S. Pat. Nos. 5,712,352 and 5,763,543. In another specific embodiment,the process is operated by introducing a carboxylate metal salt into thereactor and/or contacting a carboxylate metal salt with the metallocenecatalyst system of the invention prior to its introduction into thereactor. In yet another embodiment, a surface modifier may be present inthe bimetallic catalyst such as disclosed in WO 96/11960 and WO96/11961.

Bimodal Polyolefin Product

The polymers produced by the processes described herein, utilizing thebimetallic catalysts described herein, are preferably bimodal. The term“bimodal,” when used to describe a polyolefin, for example, polyolefinssuch as polypropylene or polyethylene, or other homopolymers, copolymersor terpolymers, means “bimodal molecular weight distribution,” whichterm is understood as having the broadest definition persons in thepertinent art have given that term as reflected in printed publicationsand issued patents. For example, a single polymer composition thatincludes polyolefins with at least one identifiable high molecularweight distribution and polyolefins with at least one identifiable lowmolecular weight distribution is considered to be a “bimodal”polyolefin, as that term is used herein. Those high and low molecularweight components may be identified by deconvolution techniques known inthe art to discern the two components from a broad or shouldered GPCcurve of the bimodal polyolefins of the invention, and in anotherembodiment, the GPC curve of the bimodal polymers of the invention maydisplay distinct peaks with a trough. Desirably, the bimodal polymers ofthe invention are characterized by a combination of features includingthe Polydispersity values and Mz values as determined from the GPCcurves.

Preferably, other than having different molecular weights, the highmolecular weight polyolefin and the low molecular weight polyolefin areessentially the same type of polymer, for example, polypropylene orpolyethylene.

Polyolefins that can be made using the described processes can have avariety of characteristics and properties. At least one of theadvantages of the bimetallic catalysts is that the process utilized canbe tailored to form a polyolefin with a desired set of properties. Forexample, it is contemplated that the polymers having the same propertiesas the bimodal polyolefins in U.S. Pat. No. 5,525,678 can be formed.

The bimodal polymers, typically ethylene based bimodal polymers, have adensity in the range of from 0.920 g/cc to 0.980 g/cc in one embodiment,preferably in the range of from 0.925 g/cc to 0.975 g/cc, morepreferably in the range of from 0.930 g/cc to 0.970 g/cc, even morepreferably in the range of from 0.935 g/cc to 0.965 g/cc, yet even morepreferably in the range from 0.940 g/cc to 0.960 g/cc.

The bimodal polymers, and in particular, the bimodal polyethylenes ofthe present invention can be characterized by their molecular weightcharacteristics such as measured by GPC, described herein. The bimodalpolymers of the invention have an number average molecular weight (Mn)value of from 10,000 to 50,000 in one embodiment, and an weight averagemolecular weight (Mw) of from 80,000 to 800,000. The bimodal polyolefinsof the present invention also have an Mz value ranging from greater than900,000 in one embodiment, and from greater than 1,000,000 in oneembodiment, and greater than 1,100,000 in another embodiment, and fromgreater than 1,200,000 in yet another embodiment. The bimodal polymershave a molecular weight distribution, a weight average molecular weightto number average molecular weight (M_(w)/M_(n)), or “Polydispersityindex”, of from 10 to 80 in one embodiment, and from 12 to 50 in anotherembodiment, and from 15 to 30 in yet another embodiment, wherein adesirable embodiment comprises any combination of any upper limit withany lower limit described herein.

The bimodal polymers made by the described processes can in certainembodiments have a melt index (MI, or I₂ as measured by ASTM-D-1238-E190/2.16) in the range from 0.01 dg/min to 1000 dg/min, more preferablyfrom about 0.01 dg/min to about 50 dg/min, even more preferably fromabout 0.02 dg/min to about 10 dg/min, and most preferably from about0.03 dg/min to about 2 dg/min. The bimodal polyolefins of the inventionpossess a flow index (I₂₁ measured by ASTM-D-1238-F, 190/21.6) of from 1to 40 dg/min in one embodiment, and from 1.2 to 20 dg/min in anotherembodiment, and from 1.5 to 20 dg/min in yet another embodiment.

The bimodal polymers described herein in certain embodiments have a meltindex ratio (I₂₁/I₂) of from 20 to 500, more preferably from 40 to 200,and even more preferably from 60 to 150, wherein a desirable range maycomprise any combination of any upper limit with any lower limitdescribed herein.

The polymers of the invention may be blended and/or coextruded with anyother polymer. Non-limiting examples of other polymers include linearlow density polyethylenes produced via conventional Ziegler-Natta and/ormetallocene catalysis, elastomers, plastomers, high pressure low densitypolyethylene, high density polyethylenes, polypropylenes and the like.

Polymers produced by the process of the invention and blends thereof areuseful in such forming operations as film, sheet, pipe and fiberextrusion and co-extrusion as well as blow molding, injection moldingand rotary molding. Films include blown or cast films formed bycoextrusion or by lamination useful as shrink film, cling film, stretchfilm, sealing films, oriented films, snack packaging, heavy duty bags,grocery sacks, baked and frozen food packaging, medical packaging,industrial liners, membranes, etc. in food-contact and non-food contactapplications. Fibers include melt spinning, solution spinning and meltblown fiber operations for use in woven or non-woven form to makefilters, diaper fabrics, medical garments, geotextiles, etc. Extrudedarticles include medical tubing, wire and cable coatings, geomembranes,and pond liners. Molded articles include single and multi-layeredconstructions in the form of bottles, tanks, large hollow articles,rigid food containers and toys, etc.

EXAMPLES Example 1

This example describes the preparation of various supportedZiegler-Natta catalysts that were modified; then activated with TMA; andthen used in separate polymerization reactions, to produce unimodalpolyethylene. The productivities of the modified Ziegler-Natta catalysts(Catalysts B and C) were substantially higher than the productivities ofthe unmodified Ziegler-Natta catalysts (Catalyst A).

The TMA activator was trimethylaluminum in heptane, and theethylaluminum sesquichloride (EASC) was in toluene; both were suppliedby Aldrich Chemical Company, Inc. The diethylaluminum chloride (DEAC)was in heptane, and the diethylaluminum ethoxide (DEAl-E) was in hexane;both were supplied by Akzo Nobel Polymer Chemicals LLC. Kaydol, a whitemineral oil, was purchased from Witco Corporation, and was purified byfirst degassing with nitrogen for 1 hour, followed by heating at 80° C.under vacuum for 10 hours.

Catalyst A samples (Samples 1-6) represent unmodified Ziegler-Nattacatalysts (not activated). Those samples were prepared in the followingmanner. Davison-grade 955 silica (2.00 g), previously calcined at 600°C. for 4 hours, and heptane (60 ml) were added to a Schenk flask toprovide a silica slurry. The flask was placed into an oil bath, whichwas maintained at 55° C. Dibutylmagnesium (1.44 mmol) was added to thesilica slurry (at 55° C.) which was stirred for 1 hour. Then, 1-Butanol(1.368 mmol) was added (at 55° C.), and the mixture was stirred foranother hour. Next, TiCl₄ (0.864 mmol) was added to the reaction medium(at 55° C.) and the resulting mixture was stirred for 1 hour. The liquidwas then removed from the slurry under vacuum to give a white freeflowing catalyst powder. Each catalyst sample was then treated withactivator. The type of activator used with each Catalyst A sample isreported below in Table 1.

Catalysts B and C represent modified Ziegler-Natta catalysts. Catalyst Bsamples (Samples 7-11 and 14) were prepared as follows, using an“in-situ” method, meaning that no filtration, washing or isolation wasinvolved in the preparation of the modified Ziegler-Natta catalyst. Themodified catalyst was ready to use by simply mixing DEAC or EASC withcatalyst A in Kaydol oil for two hours at room temperature. Thus, in aparticular embodiment of the present invention, the modifiedZiegler-Natta catalysts may be prepared without isolating theZiegler-Natta catalyst prior to contacting with the modifier.

In preparing each of those samples, a hydrocarbon solution that includedmodifier was added to a Kaydol slurry of Catalyst A (0.521 g in 13.50 gof Kaydol) at room temperature (25° C.). For Samples 7-11 the modifierwas DEAC. For Sample 14 the modifier was DEAL-E. Each resulting mixturewas stirred at room temperature for 2 hours, and then used forpolymerization. Catalyst C samples (Samples 12 and 13) were prepared asfollows, using an “isolation” method, meaning that filtration, washingand drying were involved in the catalyst preparation. In preparing eachsample, a hydrocarbon solution that included the modifier (DEAC or EASC)was added to a hexane (40 mL) slurry of Catalyst A (5.02 g) at roomtemperature. Each resulting mixture was stirred at room temperature for2 hours and then was filtered, washed twice with hexane (20 mL each),and dried under vacuum at room temperature to yield a light brown freeflowing powder.

In each of Samples 1-14, polyethylene was prepared in a slurry phasereactor using the catalysts as specified above and in the Tables below.Kaydol oil slurries that contained each of the catalysts (Samples 1-14)were prepared. For each polymerization, an aliquot of the respectiveslurry mixture was added to a 50-ml stainless steel bomb containing 50ml of hexane. The slurry reactor was a 1-liter, stainless steelautoclave equipped with a mechanical agitator. Before polymerization,the reactor was dried by heating at 96° C. under a stream of drynitrogen for 40 minutes. After cooling the reactor to 50° C., 500 ml ofhexane and 40 mL of 1-hexene was added to the reactor, followed by 1.0ml of TMA in heptane (2.0 mole, as activator). The temperature of thereactor was gradually raised to 85° C., and 90 ml of hydrogen was added(except for Samples 1, 7 and 13). The reactor was then pressured to 200psi (1,379 kPa) with ethylene. Each pre-mixed catalyst slurrycomposition was then transferred to the reactor under ethylene pressure.Heating was continued until a polymerization temperature of 95° C. wasattained. Unless otherwise noted, each polymerization was continued for60 minutes, during which time ethylene was continually added to thereactor to maintain a constant pressure. Anhydrous conditions weremaintained. At the end of 60 minutes, the reactor was vented and opened.The results of each polymerization run are set forth in Tables 1 and 2below. The number of grams of catalyst in the tables refers to theweight of the entire catalyst composition exclusive of the oil or otherdiluent that may be used with the catalyst to aid its addition to thepolymerization reactor. The productivity of each polyethylenepolymerization run was measured in grams polyethylene produced per gramof supported catalyst (entire bimetallic catalyst, including thesupport, etc., but excluding the oil or other diluent) per hour. TABLE 1Comparative Samples 1-6 of Example 1 Catalyst charged Activator/Ti YieldProductivity Sample Cat. Activator (g) (mole ratio) H₂ (mL) (g) (g/g) 1A TMA 0.0314 177 0 90.6 2884 2 A TMA 0.0306 182 90 49.3 1611 3 A TMA0.0171 325 90 22.1 1331 4 A DEAC 0.0373 149 90 43.7 1171 5 A EASC 0.0404137 90 8.6 213 6 A DEAL-E 0.0409 136 90 2.1 51

TABLE 2 Inventive Samples 7-14 of Example 1 Catalyst Modifier/Ti chargedActivator/Ti H₂ Yield Productivity Sample Cat. Modifier (molar ratio)Activator (g) (molar ratio) (mL) (g) (g/g) 7 B DEAC 1.6 TMA 0.0092 604 099.4 10757 8 B DEAC 0.8 TMA 0.01846 300 90 100.2 5428 9 B DEAC 1.6 TMA0.0166 335 90 107.5 6451 10 B DEAC 4.8 TMA 0.01835 303 90 88.2 4806 11 BDEAC 8.0 TMA 0.0187 297 90 89.3 4775 12 C DEAC 1.6 TMA 0.0176 316 9097.9 5562 13 C EASC 0.86 TMA 0.0199 280 0 152.25 7651 14 B DEAL-E 1.49TMA 0.0191 291 90 69.1 3618

As demonstrated above, the modified Ziegler-Natta catalysts (Catalysts Band C) showed improved catalyst productivities over the unmodifiedZiegler-Natta catalysts (Catalyst A). The productivities of Samples 1-6(Catalyst A) were all below 3,000 g polymer/g catalyst, while theproductivities of Samples 7-14 (Catalysts B and C) were all above 3,000g polymer/g catalyst. Note also that high productivities were obtainedfor a wide range of aluminum:titanium molar ratios, from a low of 0.8(Sample 8) to a high of 8.0 (Sample 11). However, the highestproductivities were at lower ratios, i.e., molar ratios of 0.8 and 1.6.(See Samples 7-9 and 12-14), while productivities above a molar ratio of4 (4.8 and 8.0) were lower. Also, it was observed thathalogen-containing modifiers (DEAC and EASC) performed better than theethoxide-containing modifier (DEAL-E).

Example 2

This example demonstrates how catalyst productivity can be affected bycontacting an non-activated unmodified Ziegler-Natta catalystsimultaneously with a modifier and activator, rather than firstmodifying the catalyst followed by activating it. In this example, analiquot of a Kaydol oil and non-activated Type A Catalyst (0.0191 grams)slurry was formed. This catalyst slurry was formed using the proceduredescribed above in Example 1. The catalyst slurry was introduced to a 50ml stainless steel bomb containing 50 ml of hexane. Anhydrous conditionswere maintained.

The slurry reactor was a 1-liter, stainless steel autoclave equippedwith a mechanical agitator. Before polymerization, the reactor was driedby heating at 96° C. under a stream of dry nitrogen for 40 minutes.After cooling the reactor to 50° C., hexane (500 ml) was added to thereactor, followed by 1.0 ml of TMA activator (2.0 moles) in heptane and0.025 ml of DEAC modifier (0.04 mmoles) and also 1-hexene (40 ml). Thereactor was then sealed; and the temperature of the reactor graduallyraised to 85° C. The reactor was pressurized to 200 psi (1379 kPa), andethylene was introduced to the reactor. The pre-mixed catalyst slurry(containing Catalyst A) was then transferred to the reactor underethylene pressure. Heating was continued until a polymerizationtemperature of 95° C. was attained. The polymerization continued for 60minutes, during which time ethylene was continually added to the reactorto maintain a constant pressure. At the end of 60 minutes, the reactorwas vented and opened. The results are shown in Table 3 below,productivity expressed as above. TABLE 3 Polymerization results whencombining the modifier and activator simultaneously with the ZN catalystModifier/Ti Catalyst charged Activator/Ti Productivity Sample Cat.Modifier (molar ratio) Activator (g) (molar ratio) H₂ (mL) Yield (g)(g/g) 15 A DEAC 5.8 TMA 0.0191 290 90 44.47 2340

The results, reported in Table 3, suggest that the greatest boost inactivity is seen when the modifier and activator are contacted with theZiegler-Natta catalyst separately, as reported in Table 2.

Example 3

This example describes the preparation of two different bimetalliccatalysts, reflected in Table 4, which were then used in separatepolymerization reactions to produce bimodal polyethylene, the results ofwhich are shown in Table 5.

As reflected in Table 4, a “Catalyst D” (Sample 16) was prepared asfollows. DEAC (0.1 ml or 0.16 mmol) was added to a slurry ofnon-activated Catalyst A (0.265 g) in 13.8 grams of Kaydol oil. Theresulting mixture was stirred at room temperature for 2 hours. To thatslurry was added metallocene, specificallybis(n-butylcyclopentadienyl)zirconium dichloride ((BuCp)₂ZrCl₂),supplied by Boulder Scientific Company (0.011 g, 0.0272 mmol), alongwith an activator, i.e., MAO (0.85 ml, 2.64 mmol), and Kaydol (7.2 g).The combined slurry, containing the activated bimetallic catalyst wasthen mixed and stirred for 2 hours at room temperature, resulting in“Catalyst D.”

Also reflected in Table 4 is Catalyst E (Sample 17), which was preparedas follows. A slurry was prepared, that included Kaydol oil (27.4 g) anda DEAC-modified Catalyst C (0.501 g), similar to Sample 12 in Table 2.The slurry also included metallocene, i.e., (BuCp)₂ZrCl₂ (0.026 g,0.0643 mmol) and MAO (1.2 ml, 3.63 mmol). The slurry was stirred for 8hours at room temperature, resulting in Catalyst E (Sample 17).

The bimetallic catalysts of the present invention possess a molar ratioof Ziegler-Natta transition metal to metallocene metal of from 10:1 to1:1 in one embodiment, and from 5:1 to 2:1 in yet another embodiment.The molar ratio of aluminum from the MAO activator to metallocene metalranges from 500:1 to 1:1 in one embodiment, and from 200:1 to 40:1 inanother embodiment. Specific values for the examples are shown in Table4. TABLE 4 Bimetallic catalysts Ti loading Metallocene Zr loadingCatalyst Ziegler Component (mmol/g cat) component (mmol/g cat) Ti/ZrAl/Zr D Catalyst B 0.221 (BuCp)₂ZrCl₂ 0.063 3.5 100 E Catalyst C 0.242(BuCp)₂ZrCl₂ 0.087 2.8 56

Samples 16 and 17 were used in separate polymerization runs, the resultsof which are reported in Table 5 below. Each polymerization wasconducted in a slurry phase reactor, to produce polyethylene. An aliquoteach of Samples 16 and 17 (Kaydol oil slurries) was added to a 50 mlstainless steel bomb containing 50 ml hexane. Anhydrous conditions weremaintained. The polymerization time for each run was 60 minutes.

The slurry reactor was a 1-liter, stainless steel autoclave equippedwith a mechanical agitator. The reactor was first dried by heating at96° C. under a stream of dry nitrogen for 40 minutes. After cooling thereactor to 50° C., hexane (500 ml) was added to the reactor, followed by1.0 ml of TMA (2.0 moles) in heptane. Also added were 30 micro liters ofdistilled water and 40 ml of 1-hexene. The reactor was then sealed. Thetemperature of the reactor was gradually raised to 85° C., and 90 ml ofhydrogen was added. The reactor was pressured to 200 psi (1379 kPa) withethylene. The pre-mixed catalyst (described above) was then transferredto the reactor under ethylene pressure. Heating was continued until apolymerization temperature of 95° C. was attained. Polymerization wascontinued for 60 minutes, during which time ethylene was continuallyadded to the reactor to maintain a constant pressure. At the end of 60minutes, the reactor was vented and opened. The results of thepolymerization are reported in Table 5 below. TABLE 5 Polymerizationresults of bimetallic catalysts Catalyst Catalyst Productivity SampleType charged (g) Yield (g) (g/g) FI dg/min PDI (Mw/Mn) 16 D 0.0137 93.96803 8.1 17.9 17 E 0.0137 96.3 7031 2 19.2

The term “PDI” refers to the Polydispersity Index, which is equivalentto Molecular Weight Distribution Mw/Mn, where Mw is weight averagemolecular weight and Mn is number average molecular weight, asdetermined by gel permeation chromatography using crosslinkedpolystyrene columns; pore size sequence: 1 column less than 1000 A, 3columns of mixed 5×10(7) A; 1,2,4-trichlorobenzene solvent at 140° C.with refractive index detection. A PDI value of 10 or more is usuallysuggestive of broad and/or bimodal molecular weight distribution.

Referring to Table 5, the polyethylenes produced using Samples 16 and 17were each bimodal, that is, they revealed bimodal molecular weightdistributions. The polyethylene produced using Sample 16 catalyst had anMn of 15,597; an Mw of 278,896; an Mz of 1,277,917; and a PDI of 17.9.The polyethylene produced using Sample 17 catalyst had an Mn of 16,862;an Mw of 323,121; an Mz of 1,232,261; and a PDI of 19.2.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties, reaction conditions, and so forth, used in thespecification and claims are to be understood as approximations based onthe desired properties sought to be obtained by the present invention,and the error of measurement, etc., and should at least be construed inlight of the number of reported significant digits and by applyingordinary rounding techniques. Notwithstanding that the numerical rangesand values setting forth the broad scope of the invention areapproximations, the numerical values set forth are reported as preciselyas possible.

All priority documents are herein fully incorporated by reference forall jurisdictions in which such incorporation is permitted. Further, alldocuments cited herein, including testing procedures, are herein fullyincorporated by reference for all jurisdictions in which suchincorporation is permitted.

1-26. (canceled)
 27. A bimodal polyethylene comprising ethylene derivedunits and any one or more C₃ to C₁₀ derived units; wherein the bimodalpolyethylene possesses an Mw/Mn value of from 12 to 50 and a value of Mzof greater than 1,000,000.
 28. The bimodal polyethylene of claim 27,wherein the polyethylene is formed by contacting ethylene and C₃ to C₁₀α-olefins with a bimetallic catalyst compound produced by a methodcomprising contacting: (a) a modified Ziegler-Natta catalyst made bycontacting: (i) a Ziegler-Natta catalyst comprising a Group 4, 5 or 6transition metal; with (ii) a modifier comprising a Group 13 metal; themolar ratio of the Group 13 metal to the transition metal being lessthan 10:1; and (b) a metallocene catalyst compound to form a bimetalliccatalyst.
 29. The bimodal polyethylene of claim 28, wherein the bimodalpolyethylene has a density of from 0.920 to 0.980 g/cc.
 30. The bimodalpolyethylene of claim 28, wherein the modifier is a compound or mixtureof compounds described by the formula AlX_(n)R_(3-n), wherein Al isaluminum, X is independently selected from the group consisting ofhalides, C₁ to C₂₀ alkoxides, C₁ to C₂₀ alkylamides, and combinationsthereof; and R is independently selected from the group consisting of C₁to C₂₀ alkyls and C₆ to C₂₀ aryls; and wherein n is 0, 1, 2 or
 3. 31.The bimodal polyethylene of claim 27, wherein the bimetallic catalystand olefins are combined in a slurry or gas phase reactor.
 32. Thebimodal polyethylene of claim 27 used to produce a pipe product, a filmproduct, or a blow molding product.
 33. A bimetallic catalyst,comprising a support material; a metallocene catalyst compound bound tothe support material; and a modified Ziegler-Natta catalyst bound to thesupport material; wherein the modified Ziegler-Natta catalyst is areaction product of a Ziegler-Natta catalyst comprising a Group 4 or 5transition metal and a modifier comprising aluminum; and wherein themolar ratio of aluminum to titanium is less than 10:1.
 34. Thebimetallic catalyst of claim 33, in which the bimetallic catalyst isnon-activated.
 35. The bimetallic catalyst of claim 33, in which thebimetallic catalyst is activated.
 36. The bimetallic catalyst of claim33, in which the modified Ziegler-Natta catalyst is an non-activatedreaction product of a Ziegler-Natta catalyst that includes titanium andis reacted with a modifier that includes aluminum.
 37. The bimetalliccatalyst of claim 33, in which the support material is silica.
 38. Thebimetallic catalyst of claim 33, in which the metallocene catalystcompound comprises zirconium.
 39. The bimetallic catalyst of claim 33,in which the modifier is diethylaluminum chloride.
 40. The bimetalliccatalyst of claim 33, in which the modifier is ethyl aluminumsesquichloride.
 41. The bimetallic catalyst of claim 33, in which themodifier is diethylaluminum ethoxide.
 42. The bimetallic catalyst ofclaim 33, in which the molar ratio of aluminum to titanium is less than7:1.
 43. The bimetallic catalyst of claim 33, in which the molar ratioof aluminum to titanium is less than 5:1.
 44. The bimetallic catalyst ofclaim 33, in which the molar ratio of aluminum to titanium is less than3:1.
 45. A method of producing a bimodal polyethylene comprisingcontacting ethylene and C₃ to C₁₀ α-olefins with a bimetallic catalystcompound produced by a method comprising contacting: (a) a modifiedZiegler-Natta catalyst made by contacting: (i) a Ziegler-Natta catalystcomprising a Group 4, 5 or 6 transition metal; with (ii) a modifiercomprising a Group 13 metal; the molar ratio of the Group 13 metal tothe transition metal being less than 10:1; and (b) a metallocenecatalyst compound to form a bimetallic catalyst.
 46. The method of claim45, the molar ratio of the Group 13 metal to the transition metal isfrom 0.5:1 to 5:1.
 47. The method of claim 45, wherein the modifier is acompound or mixture of compounds described by the formulaAlX_(n)R_(3-n), wherein Al is aluminum, X is a halide, and R isindependently selected from the group consisting of C₁ to C₂₀ alkyls, C₁to C₂₀ alkoxides, C₁ to C₂₀ alkylamides, and combinations thereof; and nis 0 to
 3. 48. The method of claim 45, wherein the modifier is acompound or mixture of compounds described by the formulaAlX_(n)R_(3-n), wherein Al is aluminum, X is independently selected fromthe group consisting of halides, preferably fluoride, chloride orbromide, C₁ to C₂₀ alkoxides, C₁ to C₂₀ alkylamides, and combinationsthereof; and R is independently selected from the group consisting of C₁to C₂₀ alkyls and C₆ to C₂₀ aryls; and wherein n is 1, 2 or
 3. 49. Themethod of claim 45, wherein the Ziegler-Natta catalyst is not activated.50. The method of claim 49, wherein the modified Ziegler-Natta catalystis not activated.
 51. The method of claim 45, wherein the Group 13 metalis boron or aluminum.
 52. The method of claim 45, wherein the Group 13metal is aluminum.
 53. The method of claim 45, wherein the bimetalliccatalyst additionally includes a first activator in an amount sufficientto activate the modified Ziegler-Natta catalyst.
 54. The method of claim53, wherein the first activator is an aluminum alkyl in combination withwater.
 55. The method of claim 54, wherein the molar ratio of water toaluminum alkyl ranges from 0.01 to
 5. 56. The method of claim 54,wherein the water and aluminum alkyl are added simultaneously with thebimetallic catalyst in a polymerization reactor.
 57. The method of claim45, wherein the bimetallic catalyst additionally includes a firstactivator for activating the modified Ziegler-Natta catalyst, whereinthe first activator contains aluminum, and wherein the molar ratio ofthe first activator aluminum to the Ziegler Natta transition metal isgreater than 10:1.
 58. The method of claim 57, wherein the molar ratioof the first activator aluminum to the Ziegler Natta transition metal isgreater than 15:1.
 59. The method of claim 57, wherein the molar ratioof the first activator aluminum to the Ziegler Natta transition metal isgreater than 20:1.
 60. The method of claim 45, wherein the bimetalliccatalyst additionally includes a second activator in an amountsufficient to activate the metallocene catalyst compound.
 61. The methodof claim 60, wherein the second activator is methyl aluminoxane (MAO) inan amount sufficient to activate the metallocene catalyst compound. 62.The method of claim 45, wherein the molar ratio of the Group 13 metal ofthe modifier to the transition metal is from 0.5:1 to 7:1.
 63. Themethod of claim 45, wherein the molar ratio of the Group 13 metal of themodifier to the transition metal is from 0.5:1 to 5:1.
 64. The method ofclaim 45, wherein the molar ratio of the Group 13 metal of the modifierto the transition metal is from 0.5:1 to 3:1.
 65. The method of claim45, wherein the Ziegler-Natta catalyst is formed by contacting anorganomagnesium compound comprising at least one alkyl group with aGroup 4 or 5 transition metal halide, alkoxide or oxide compound. 66.The method of claim 45, wherein the Ziegler-Natta catalyst is formed bycontacting an organomagnesium compound with titanium tetrachloride,wherein the organomagnesium compound has the formula Mg(OR)₂ or R¹_(m)MgR² _(n); where R, R¹, and R² are alkyl groups, and m and n are 0,1 or
 2. 67. The method of claim 45, wherein the modified Ziegler-Nattacatalyst is supported on a support material.
 68. The method of claim 45,wherein the metallocene catalyst compound is activated prior tocontacting.
 69. The method of claim 45, wherein the components in steps(i) and (ii) of step (a) are combined prior to entering thepolymerization reactor.
 70. The method of claim 45, wherein thebimetallic catalyst has a productivity greater than 4,000 g polymer/gcatalyst at from 80 to 100° C. in a gas phase polymerization reactor.71. The method of claim 45, wherein the bimetallic catalyst has aproductivity greater than 6,000 g polymer/g catalyst at from 80 to 100°C. in a gas phase polymerization reactor.
 72. The method of claim 45,wherein the component in step (ii) is combined simultaneously withtrimethylaluminum in a polymerization reactor; and wherein the componentin step (ii) excludes trimethylaluminum.
 73. A bimodal polyethylenecomprising ethylene derived units and any one or more C₃ to C₁₀ derivedunits; wherein the bimodal polyethylene possesses an Mw/Mn value of from12 to 50 and a value of Mz of greater than 1,000,000 made by the methodof claim 45.